Where you made your mistake is appearing that you were talking on the phone. Next time don't hold your GPS up to your ear. Close your windows if you can't hear it.
As for court, you better have proof you were not on the phone or texting at that moment. They could assume your GPS defense is a falsehood since holding a GPS up to your ear is uncommon. And, you should hope that the Spriggs decision has 'filtered down to the rank & file' judges. A judge may not want to get schooled by a defendant in his courtroom on a 5th District Court of Appeals Decision.

